Taste is an interesting and useful model of the capacity of nerve cells to control their targets. Taste axons profoundly alter the structure and function of taste buds and the neighboring epithelium. The overall objective is to use immunocytochemistry and allied techniques to evaluate rabbit, rat and gerbil gustatory epithelium and adjacent non-gustatory epithelium by utilizing a panel of lectins and a panel of antibodies to keratins. Cells of taste buds and the basal cells of gustatory epithelia have unique keratins and glycoconjugates. The evaluation of antibodies against the 19 soft keratins found in diverse epithelia helps to diagnose which of the many epithelia is the source of metastasizing cancer cells. The specific aims are directed toward the evaluation of seven hypotheses associated with the following four programmatic areas of research on taste buds and their neural control: I. To characterize the gustatory epithelium and taste buds by using lectins, and by using antibodies to keratins. II. To analyze epithelial organization, including cell lineage pathways leading to taste buds. III. To utilize denervation to evaluate the neural control of cellular properties such as epithelial cell differentiation, taste cell longevity and the rate and locus of the division of basal and suprabasal epithelial cells. IV. To examine lectin binding and keratin expression in gustatory epithelia during the development and regeneration of taste buds. The discovery of differentiation markers for subsets of cells that generate taste buds will aid those experiments that examine neural interactions within the gustatory epithelium. Thus, these studies are designed to yield important information about the existence of subclasses of cells resident in gustatory and adjacent epithelium and about the neural control of properties of these cells.